Gagena Reservoir   Be the first to submit input for Gagena Reservoir. If you have info on Gagena Reservoir, Dawson County, Montana please submit it here to improve this web site.          These outdoors activities are available near Gagena Reservoir.   Public Lands Near Gagena Reservoir: Makoshika State Park, Montana, 14 miles away Medicine Rocks State Park, Montana, 40 miles away   Hotels Near Gagena Reservoir: Super 8 Glendive, Glendive, 16 miles away Days Inn Glendive, Glendive, 16 miles away Comfort Inn Glendive, Glendive, 16 miles away Knights Inn Glendive, Glendive, 16 miles away Beaver Creek Inn and Suites, Wibaux, 23 miles away